


Omegaverse Appendix to Unwritten

by PorcupineGirl



Series: Unwritten 'verse [2]
Category: Supernatural
Genre: Alpha/Beta/Omega Dynamics, Biology, Biology Inaccuracies, Clinical descriptions of sex acts, Evolution, Human Biology, Multi, Non-Traditional Alpha/Beta/Omega Dynamics, Other
Language: English
Status: Completed
Published: 2015-10-28
Updated: 2015-10-28
Packaged: 2018-04-28 14:04:36
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5093480
Author URL: https://archiveofourown.org/users/PorcupineGirl/pseuds/PorcupineGirl
Summary: <blockquote class="userstuff">
              <p>This is an appendix to the fic Unwritten, giving a background of the biology and sociology of sex and gender in its omegaverse.</p>
            </blockquote>





	Omegaverse Appendix to Unwritten

**Welcome to PG's Magical Land of Overthinking Omegaverse!**

When I decided I wanted to write an alpha/alpha omegaverse story, I realized that I could only write anything more involved than a simple PWP if I made the universe make sense to me. I try to just suspend disbelief when reading omegaverse, but there are many things that get handwaved away that nag at me. 

At the very least, I wanted a plausible (very loose definition of "plausible" here) explanation for why humans would evolve to have some individuals with estrus cycles and some with menstrual cycles, given that _no known species has ever done this._ Also, why there would still be concepts of male/female in such a society instead of alpha being synonymous with male and omega synonymous with female—and let me tell you, I very nearly did cut male omegas and female alphas out entirely. But laziness won out because I'd already mentioned them a bunch of times in the story by the time I made that decision. I could not, however, find any possible way to explain away the idea of male omegas' butts being connected to their uterus when nobody else's are. Especially if we're to believe that you don't know if you're an alpha or an omega until you present.

Once I started on this quest for biological plausibility, the magical undertones of most "true mates" type experiences had to go out the window, as well. Now, I love me some magical realism soulmate AU, including omegaverse. But I can only swallow it if it's magical or at least handwaved enough that it might as well be. So I sort of had to make a version of true mates that did not actually rely on fate/destiny, even though it _seems to_ and many people/societies _think_ it does.

You will notice that a whole shitload of this is never mentioned in the fic, and is completely unnecessary for reading or understanding it. Didn't stop me from working it all out. :P (Granted, I didn't necessarily know in advance whether a particular bit of information might come in handy.) 

**Sex/Gender**

I will use "sex" to refer to A/B/O status and "gender" to refer to male/female. Because male omegas and female alphas make up only about .2% of the population, females are assumed to be the ones who will grow up to bear children whether as an omega or a beta, and so the social construction of M/F gender has followed much of the same path as our own. It's assumed that everyone who is not intersex will be beta until they present otherwise, so children are raised just as male/female.

The male/female dichotomy has one additional biological marker beyond chromosomes, genitalia, and secondary sex characteristics as in our universe—pheromones. Just as alphas, betas, and omegas can be distinguished by scent after presentation, males and females give off distinct pheromones from birth. In the case of children born with both a penis and vagina (see Male Omegas and Female Alphas below), these pheromones are used to assign gender at birth.

As in our universe, in most cases these biological markers align and the person grows up to be cissexual with a gender that also aligns with them and the gender they were assigned because of them. But in the end, pheromones are no more a guarantee of gender than any other biological marker and a child assigned a gender based on these pheromones may not identify with their assigned gender and instead identify as transgender or genderqueer.

It is also possible for people to identify as transsexual, though it is less common. In this case, a person presents as alpha, beta, or omega at puberty but does not identify with this sex.

**Biology and Evolution**

Humans are the only living species to make use of both estrus cycles and hidden menstrual cycles, though this double fertility cycle pattern seems to have been present in ancient hominids including Neanderthals who lived alongside modern humans. Evidence of both types of cycles has been found as far back as Australopithecus afarensis; it is thought that it may be the result of inbreeding between menstrual humans and another species of primate that experienced estrus.

Evolutionarily, it is believed to be a population control mechanism. People can be genetically predisposed to be a male alpha or female omega, but environmental factors cause epigenetic changes that result in presentation at puberty. Alpha/omega pairs tend to produce more offspring than pairs with a beta. This is not because they are inherently more fertile, but because (before modern suppressants and birth control) of the mechanics of the heat cycle. Omegas are only fertile when in heat (which happens 3-4 times per year), and many omegas are only receptive to sex during heat. When they do go into heat, a mated omega and their alpha are irresistible to each other, and the combination of guaranteed egg release, guaranteed sex, slick that increases the motility of sperm, and knotting to ensure that the semen does not escape, a mated omega in heat will become pregnant around 80% of the time.

Omegas do not go into heat for about two years after giving birth, but will usually get pregnant again during their first heat afterwards. So a mated A/O pair, with no suppressants or birth control, will typically produce a child every three years like clockwork from the time they blood bond to the time that the omega goes through menopause in their mid-forties. This means that, taking into account historical childhood death rates, the average mated A/O pair usually produces 7-8 children who live to be adults, whereas the average A/B, B/B, or O/B couple will only produce three or four.

A/Os are more common in rural areas and less common in urban areas. Living in close quarters reduces the odds of presenting. So it is believed that the epigenetic changes that lead to presentation are sensitive to population needs and will cause presentation when the population is low and suppress presentation when the population is high. In the United States (and much of the Western world), currently the population is about 80% betas and 20% alphas/omegas. In some countries suffering from overpopulation, though, such as China and India, the proportion of alphas and omegas can be as low as 5%, especially in urban areas.

(Note: Too many alphas in a small area may attack/kill each other, possibly another factor that led us to evolve low presentation rates when overcrowded.)

**Male Omegas and Female Alphas**

Male omegas and female alphas are extremely rare and are the result of specific genetic mutations. It runs in families but the inheritance pattern is complicated and not fully understood yet. They are a type of intersex, being born with both a penis and a vagina (as well as both testicles and ovaries). It cannot be determined whether they are Alpha or Omega until puberty, but they nearly always do present. (Intersex betas are possible but exceedingly rare.) They are identified as male/female by pheromones rather than genitalia. They are generally only fertile according to their sex, not their gender - but can often have and enjoy sex with either their penis or vagina. About 5% of all A/O individuals are born intersex, but only about 20% of those births result in a male omega or a female alpha. (Meaning these two groups together make up about .2% of the population.)

Some cultures revere these individuals, but historically there have also been many cultures who practice infanticide on them. This is illegal in most of the modern world, but happens anyhow in some very traditional cultures or families. In general, in the modern Western world they are raised according to their gender, since most of the time they will present accordingly (males presenting as alphas, females presenting as omegas). Those who present MO/FA are often subject to more harassment and discrimination than female betas or omegas. 

**Types of Attraction**

Unlike in our world where there are generally two types of attraction, romantic and sexual, there is a third type of attraction: chemical, which is an attraction based on pheromones. This is only experienced consciously by alphas and omegas, although betas do respond to a lesser extent to pheromones even if they can't consciously smell them.

Chemical attraction often, but not always, goes hand-in-hand with sexual attraction. In most cases, people will only feel a chemical attraction to people they are also sexually attracted to, although asexual people can also experience chemical attraction.

Because people's pheromones begin as genetically determined but are the influenced by their experiences throughout their life, people with compatible personalities tend to also have compatible pheromones and vice-versa. This is true even in non-romantic relationships; good friends are often more attuned to each others' smells than strangers.

Because of this, generally if people start out as strangers but are romantically attracted to each other, date, and fall in love, over time their pheromones change to line up with each other. This process is known as scent bonding. If two people are already extremely compatible they may, in rare cases, form a spontaneous scent bond—a case of extremely strong chemical attraction _before_ romantic attraction or love is involved. Chemical attraction this strong, paired with sexual attraction, can make a couple feel like they are in love even if they barely know each other. Over time, the initial hormone rush recedes and typically real romantic attraction and love develop quickly.

**Bonding**

Alpha/Omega pairs form scent bonds first as their pheromones adjust to each other. This is usually a gradual process that takes place over months or years, but almost always takes at least six months of dating/courtship (occasionally friends who are romantically and sexually attracted to each other will develop scent bonds before they have become romantically involved - but this is not nearly as common as romantic comedies would have people believe). Alphas and omegas can also scent bond with betas, though only the alpha or omega is consciously aware of the bond (it has been chemically proven that betas can scent bond, but neither is consciously aware of it and it does not always happen even in beta/beta pairs who are together for decades). When a pair are strongly scent bonded, their scents (and the tastes of their saliva and other bodily fluids) are extremely attractive to each other; most describe it as the best smell/taste they've experienced. This leads to additional oxytocin and other bonding hormones being released when they are near each other, which strengthens their emotional bond further.

Once a solid scent bond is established, alpha/omega pairs can blood bond. They cannot blood bond with betas. This requires four sets of hormones: one found in the omega's blood, one in the alpha's saliva, one in the omega's slick, and one in the alpha's semen. The alpha must be exposed to the omega's blood and slick via their mouth and knot, while the omega is exposed to the alpha's saliva and semen through their blood and vaginal walls. This is typically done by the alpha biting the omega's neck while knotting them and ejaculating into their vagina. A blood bond will not take if the scent bond is not strong enough, because the couple's pheromones are not lined up properly yet; even with an appropriate scent bond about 10% of blood bonds will take two or three tries.

Given that many (though not all) omegas are only receptive to sex and only produce slick when they are in heat, historically a blood bond generally required a risk of pregnancy. Modern birth control can allow an omega to experience heats without becoming fertile, although of course their effectiveness is not 100%.

Once they have performed a blood bond, the two are considered mates. Their pheromones and hormones immediately sync up further, blending their scents into a new one that is just as attractive to each of them while being unattractive (though not necessarily unpleasant) to other alphas and omegas. Other people's pheromones immediately are less attractive to them as well, and their physical attraction to anyone other than their mate diminishes greatly. Because of this, cheating is rare among mated couples, though of course there are exceptions to every rule. 

During the omega's heat, their scents are irresistible to each other (and the scent of other alphas/omegas becomes repulsive) and it is rare for mated couples to _not_ spend the entire heat period having sex. The blood bond also increases the omega's fertility during heat, so without birth control or heat suppressants mated omegas will get pregnant around 80% of the time that they go into heat. Mating can sometimes diminish the effectiveness of birth control or suppressants, and so alpha/omega couples sometimes get married but don't blood bond until they want to start having children, or at least are okay with the idea of having children. Those who are certain they do not want children often do not form a blood bond until one or both has been sterilized (unfortunately, the childfree face the same prejudices against sterilization in their 20s as in our world).

A very small percentage of alphas and omegas, around 3-5%, will form a spontaneous scent bond. This means that as soon as two people meet, their pheromones are as in sync as a couple who have developed a strong scent bond. Because it happens so suddenly, though, rather than over months or years, the physical reaction is usually very intense and feels more like a mated pair when the omega is in heat, with their scents irresistible to each other. The urge to blood bond is extremely strong, and the blood bond will almost always take on the first try. Generally two people who experience a spontaneous scent bond are referred to as "mates" even if for some reason they do not or cannot blood bond immediately or at all. This stems from the traditional belief (common to many cultures) that the two were destined to be each others' mates since birth, and the temporary absence of a blood bond cannot interfere with that fact.

The biology of SSBs is not yet fully understood. What has always been known anecdotally and is now being confirmed scientifically is that the couples are almost always extremely compatible personality-wise; if they had mutual friends or acquaintances before meeting those people are rarely surprised to find out about the bond, and a good number of SSBs are the result of being introduced by people who think the pair will get along. What is clear is that SSBs do not _always_ happen the first time a couple ever meets; there are reports of people who are reintroduced to someone they have not seen in many years, who did not have a SSB before but suddenly do. This led scientists to believe that the SSB is not entirely genetic (and thus not necessarily determined at birth), which has since been confirmed. People's pheromones change over the course of their lives, and a SSB is the result of pheromones that have become synced up due to a combination of genetic and environmental factors. It is possible, maybe even likely, that a couple who experiences a SSB would not have had it if they'd met several years earlier or several years later, depending on their personal developmental trajectories.

The intensity and suddenness of the bond can have many other effects as both parties' bodies try to catch up hormonally to where their pheromones already are. It is impossible to predict which, if any of these, a particular couple will experience, and occasionally couples will report effects that appear to be a result of the bond but have not been seen before (or extremely rarely). It is possible that some of these are psychosomatic, but when it comes to pheromones, hormones, emotions, and coupling behavior the line between "psychosomatic" and "physical" causes is blurry at best. If the emotions causing a physical response are the result of a hormonal swing that in turn was caused by pheromones, is it psychosomatic?

The most common effects seen in SSBs that are not usually seen in traditional scent bonds, beyond the intense desire to have sex and form a blood bond, include: a desire to tell your mate everything about yourself and learn everything about them (after sex, generally, but sometimes even during); a compulsion to be honest with your mate even if it would be to your disadvantage; a nesting instinct that can take many forms (wanting to bring your mate to your house, wanting to go to theirs, wanting to immediately select a new home together, wanting to clean or improve your living space); extreme protectiveness; and a desire to ensure that your mate is well-fed or has their favorite foods available.

**Sexuality**

Most people have both a preferred sex and a preferred gender. Most betas are heterogender but trisexual; male betas are attracted to females whether the female is omega, beta, or alpha, and vice-versa. Most alphas and omegas, on the other hand, are heterogender and heterosexual—alphas are attracted to only betas and omegas, but only of the other gender, while omegas are attracted to betas and alphas of the other gender. These combinations of sex and gender attraction are considered "straight" in the modern English-speaking world and encompass most fertile pairings. Historically, any pairing that can make babies has been considered religiously and legally acceptable almost universally: MO/MA, MO/FA, MB/FO, MB/FB, MA/FO, MA/FB, FO/FA, FB/FA. However, male omegas or female alphas paired with someone of the same gender may face discrimination from betas who cannot smell their sex and assume that they are betas/male alphas/female omegas.

In the modern US, "straight" refers to any pairing that can produce offspring, or to a person who is attracted only to people with whom they could produce offspring. However, nonfertile heterogender pairings and the people in them may be lumped in under this umbrella as noted below.

Cultures vary widely in how they perceive FA/MA, FA/MB, MO/FO, and MO/FB couples. In some cultures this is just as taboo as any other pairing that cannot produce offspring, but in most there is leniency for several reasons. 

For one, because the vast majority of heterogender pairings are combinations that can produce offspring, and betas (~80% of the population) usually cannot tell that a female is an alpha or a male is an omega until they are told, it is just simpler for the beta majority to lump all heterogender couples together so that they don't have to even consider the sexes of people in heterogender couples (society tends to be very betanormative in many ways). 

In cultures where intersex children are raised _expecting_ to be male alphas or female omegas (such as most of the modern Western world), there is often some amount of pity for male omegas and female alphas and thus people are hesitant to tell them they cannot pursue groups that they were raised expecting to be attracted to. Also, because there are few male omegas or female alphas, many people who are heterogender assume they are straight until they happen to meet a male omega or female alpha to whom they are attracted, so it is often less messy to accept these pairings than to make so many "straight" people question their sexuality. 

And finally, because these pairs can have PIV sex, many people consider them to be exactly like straight couples where one or both is infertile. In the US, historically these pairings have been considered unappealing but acceptable, and at no point were they illegal. Currently, most of the country is indifferent to these pairings and categorize them as straight, although some very conservative religions do forbid it.

Other same-gender pairings have about the same status that homosexual couples have in our current world: MO/MO, MO/MB, MB/MB, MA/MB, MA/MA, FO/FO, FO/FB, FB/FB, and FA/FA.

Individuals may be attracted to any combination of the two genders and three sexes, and some people are only attracted to particular gender/sex combinations.

Alpha/alpha couples are extremely rare regardless of the gender of the alphas. This is because it is very rare that two unrelated alphas would be able to spend enough time together to fall in love or form a scent bond. (MA/FA is also extremely rare for the same reasons, even though it is considered acceptable.) This is because alphas produce a hormone called alphasine, which is unpleasant to other alphas. Reactions between two alphas range from simply thinking they smell horrible to generally being in a bad mood around them to outright aggression.

Almost the only way for an alpha/alpha pairing to work is a spontaneous scent bond, when their pheromones are completely compatible from the moment they meet. In modern times, sometimes alphas will meet online and fall in love, but it often falls apart when they meet and they do not yet have a strong enough bond to cancel out the alphasine. There have been a few reported cases where it has brought their pheromones into alignment enough, but it is also possible that those couples would have had a spontaneous scent bond upon meeting regardless of finding each other online first. Because MA/MA and FA/FA couples are so rare, many people are not even aware that they exist and so they may face even more stigma than other same-gender couples. Alpha/alpha couples that have managed to scent bond can blood bond like an alpha/omega couple by biting each other and spreading each alpha's semen on the other's knot.

Omega/omega couples rarely blood bond, though it is possible. Neither has the drive to bite the other, nor the sharp edges on their canine teeth that alphas use when blood bonding, and increasing the intensity of their heats or their desire during heat for a partner who does not have a knot is not something most are interested in. They can enjoy sex during regular heats, usually with the help of knotting toys though fisting is also common, but those O/O pairs who have blood bonded have reported that the toys are much less satisfying during the more intense heats than before they bonded. Fisting fares better, as it is their partner's body, but it is still somewhat diminished and not all O/O couples are interested in that act to begin with. Most O/O couples are satisfied with scent bonding, just as with couples where one partner is a beta. Because omegas are not provoked by each others' pheromones the way alphas are, omega/omega couples can date and develop scent bonds over time just like most other pairings.

 

**Author's Note:**

> Let me know if you have questions or if you think something here contradicts itself or doesn't make sense!


End file.
